George j



G. 1. MURnocK. .SELF SEALING FUEL TANK. APPLICATION FILED JVUNE 23.i911.

TatendAug. 12,1919.

@mento/z Gli-:ofi E J. MURDOCK v GEORGEJ'. HUBIDOCX, 0F NEWARK, NEWJERSEY.

SELF-SELLING FUEL-TANK.

Specication of Letters Patent.

Patented Aug. 12, 1919.

Application led 'June 23, 1917. Serial No. 176,591.

To all lwlw/m. it may concern:

Beit known that I, GEORGE J. Munnocx, a citizen of the United States,residing at Newark, in the county of Essex and -State of New Jersey,have invented certain new and useful Improvements in Self-SealingFuel-ATanks, of which the following is a specification, reference being had tothe accompanying` drawings. y v

his invention relates to tanks, andparticularly to tanks for containinggasolene,

such as are used in military automobiles,

In -all gasolene or other fuel-tanks of the character above stated,known to me, a bullet passing through the tanks allows the gaso? lene toescape and Where a pressure tank is in use, that is, a tank having aforced feed duelto air pressure, several bullet holes will quickly'empty the tank. Furthermore, the escaping gasolene runs out onto theaeroplane or other structure and is frequently set A on `fire by theengine exhaust, the firing of machine guns, or by other flame.

A further object of the invention is to provide a tank free from thedefect above noted, which shall be light in weight and in which thepunctu'res made by a bulletwill close or become .plugged tosuch anextent that an aviator may at least get back to his lines, after havingbeen fired upon and having had his gasolene tank punctured.

A further object is to provide a tank surrounded by a sheet of rubber orother elastic and relativelythick material, and to provide a/ sheet orlayer of relatively brittle and easily comminuted material disposed uponthe sheet of rubber, this material being of such character that a bulletstriking 1t and 'passing through it and through the sheet of rubber willpulverize the material of the relatively brittle layer and by reason ofthe vacuum caused by the passage of the bullet will draw this comminutedY or pulverized material into the relatively 'small opening made by thebullet in its passage through the rubber layer.

A further object of the invention is to pro vide a metallic gasolene`containerwith a protective covering, consisting of one o r more layersof wood, preferably light in weight and relatively stiff and brittle,with an intermediate layer of rubber or like elastic material, whichwill expand to the passage of the bullet, but will immediately contractso that only a small opening is left through the rubber.

And a further object is to provide means for preventing the splitting ofthe Wooden layers. i

' Other objects will appear in the course of the following'description.

My invention is illustrated in the accompanying drawings, wherein Figure1 is a top plan view of a tankconstructed in accordance with myinvention;

Fig. 2 is a side elevation thereof;

Fig. 3 is a sectional view on the line 3-3 ofFig. 1;

Fig. 4 is an enlarged detail horizontal section. of one corner of thetank;

Fig. 5 is a fragmentary horizontal section showing the manner in which ahole in the tank is automatically plugged.

Referring now particularly to Fig. 5, which shows a fragmentarysectional View through thewall of, a container, 14 designates an innercasing of sheet metal, which forms the container proper. Disposedagainst this casing 14 in Fig. 5 is illustrated a layer 11.0f wood,preferably white wood,

for a reason which will be later stated, angl` illustratedas disposedagainst this layer of White wood is a layer 12 of rubber, this rubberbeing approximately thick. Disposed against the rubber-layer 12 is asecond layer n of wood 13, which is preferably white Wood.

The rubber is placed between the beards orf wooden layers 13 and firmlyglued or ce? mented thereto.' If a bullet is now fired from a rifle inthe manner indicated in this ligure, the point of the bullet strikingthe layer 13 pierces this wooden layer and breaks up andcomminutesor'pulverizes the fibers of the Wood 13 and passes throughthe rubberlayer 12. This rubber layerexpands. because of its elasticity, `topermit the passage of the bullet and then the bullet passes on throughthe layer 11. The opening through the rubber layer closes almostinimediately and the exit end of this opening is extremely small incomparison With/the size of the caliber 'of the bullet. The passage ofthe bullet through the'wall causes 'a vacuum behind the b ullet onaccount of the clinging nature of the rubber and themakes a sort of acup-shaped and relatively large entrance `opening and the pulverizedwood which is drawn in behind the bullet forms a button a between thelayer 13 and the rubber layer 12. This button compresses the rubber andcauses it to still more firmly grip the plug so that this plugeffectually seals up the hole made through the rubber by thebullet andwill stand much greater pressure than the pressure which is used in thetank for causing the gasolene to flow by force feed to the engine. Itwill be noted that the exit end of the perforation through the layer 13is slightly larger than that part of the perforation adjacent the exitend, so that the plug a is held firmly in place against any pressurewithinthe tank. A

It is particularly important to have both the wood and rubbei` ofapproximately the right thickness, as if the rubber layer is too thin,the hole made by the bullet will be relatively large and the vacuumcaused by the bullet will draw both the plug and the button ofpulverized wood through the rubber, leaving an open hole through whichthe gasolene, especially under pressure, will. escape. If, on the otherhand, the rubber is too thick, the hole through which the bullet haspassed -may partly close before the head or button has time to form. Ifthe wooden layers 11 and 13 are too thick, a needless amount of wood isadded to the tank and it adds needlessly to the amount of pulverizedwood driven inward in front of the bullet. If the wooden layers are toothin, then sufficient pulverized wood may not be formed to make thebutton and plug.

After many experiments I have found,'all things considered, that therubber layer 12 should be approximately 11; thick and that the woodenlayers should be approximately thick. Furthermore, in the course ofextended experiments, I have found that white wood is the best wood forthe purpose, by

reason of its being light in weight, stiff, and l very brittle whenbroken across the grain. This wood is, therefore, easily pulverized bythe bullet. It will be seen that the essential principle of thisinvention is to enable the bullet to plug the hole by first pulverizingthe soft or brittle material, whether it be wood or other substance, andthen by means throughout its entire length, but if the" rubber layer becemented to the rear face of the board or plank, then the hole made bythe bullet will invariably` be tapered, the smaller end being next tothe rubber, and that where two wooden layersv are used onV each side ofa rubber layer, the hole will have the form illustrated in Fig. 5, thatis, the perforation in the plank 13 will be inwardly tapering, therubber will have a relatively large entrance end to the perforation, anda relatively sniall extension through to the rear side of the rubber,and that the perforation through the plank 11 will be outwardly flared.

Fig. 5 shows the general principle of my invention and, of course, thisprinciple may be appliedto tanks of various constructions and ofdifferent details, In the drawing, however, I have shown my invention asapplied to a particular form of tank such as is used with the Curtissaeroplane. This isa pressure tank, that is a tank wherein the gasoleneor other fuel is forced out from the tank by compressed air within theupper portion of the tank. As illustrated, the tank is about two feetsquare in plan and about 14. inches deep, with somewhat rounded corners.The tank is formed of sheet metal, as for instance sheet tin,'which isdesignated 14. One head 'of this tank 14 is put in place and then thedelivery pipes, the filling pipe and the air inlet pipe are put'inplace, that is, the nipples for these pipes areput in place. In thefigures, 15 designates the pipes through which the gasolene is forced tothe engine. Two of these delivery pipes 15 are used so that if oneshould be cut off, the other would continue to supply the engine. 16designates the inlet through which ifuel is filled into the container ortank. The nipple 17 connects to means whereby air may be forced into theupper portion of the tank to exert a pressure on the liquid containertherein. After the outlet nipples 15,16 and 17 are put in place, theother head of the container is put in. This completes they metal portionof the container. The container is now Jinclosed within a sheathing ofwood, rubber and cotton duck constructed as will now be described. v

'The inside layer of wood 11 is glued to a layer of cotton lduck 18, thegrain of the wood extending lengthwise of the tank, and

holes being made in the proper places for the passages of the nipples15, 16 and 17. After the glue between the wood and the sheet of cottonduck is nearly dry, the outside face of the wooden layer 11 is scoredVso as to make it rough. The rubber layer I 12 is also scored on bothfaces and holes made in it to correspond to the nipples 15,

16 and 17. The surface of the wooden layel 11 and the inner surface ofthe rubber layer are now covered with glue and the rubber is wrappedaround the layer of Wood, that is, extends transversely of the tank, theends of the rubber layer being cemented together as at 19. The rubber isnot stretched, however, and the ends ofthe rubber are vulcanizedtogether. The layer of rubber is slightly Wider than thelength of thewooden layer 11 for a urpose which Will be later stated. Small liardwood pegs 20 are now driven through the rubber into the wood 11 so as tocause the rubber to lie'flat at all parts until the glue is dry. The useof nails or screws in the construction is omitted as far as possible,the hard wood pegs or pins being used instead.

When the rubber layer is firmly attached to the boards or lank 11, the-outer layer 13 of wood is placedJuponthe rubber, theinner face of thewood being scored. This outer layer is glued or cemented firmly to therubber, holes being made for the nipples to pass throu h, of course. Alayer oi heavy cotton duc 21 is now lued to the outer layer of wood andthen rass bands 22 are tightly secured upon the tank like hoops. Thetank is now kiln dried until all moisture from the glue is dispelled.The heads composed of two layers of plank 11 and 13 with an intermediatelayer 12 of rubber and the inner layer of duck are now put in place. Theheads are constructed in precisely the same manner as described for thebody of the container, the only difference being that the inner layer11a of wood is small enough in outside measurement to t closely insidethe layer of rubber 12 at the sides of the tank. This layer 11a of woodis now glued and pinned to the projecting ends of the top, sides andbottom of the tank. The rubber layer 12EL is then put in lace in themanner heretofore described, t e edges of the rubber layer being scored,as well as the faces, and vulcanizing rubber cement is applied to theends or edges of the rubber 12EL so as to engage it with the rubbersheet 12. It will now be seen that as the continuous sheet of rubberwhich surrounds the tank is vulcanized together at 19 and the ,sheetsforming the heads or ends are vulcanized together at their edges, thereis an unbroken casing of rubber surrounding the gasolene containerl andthe inner layer of wood. The outer layer of wood 13a is now glued to theouter surface of the rubber 12 and small hard wood pins 23 are driventhrough both layers of wood and the layer of rubber, this outer layer ofwood being also pegged and glued to the ends of the wood layer 13, theouter wooden layer is now covered with cotton duck 21"L and the wholecontainer painted withv rep oof paint 24 or in place of this the whole owith thin tin or aluminum:

The object of using the cotton duck fabric 18 and 21 is to prevent thewood from ntainer may be covered splintering and splitting as thebullets vpass through it and further it assists in keeping the wood fromwarping. If a bullet should strike one of the hard woodpegs 23 or 20used in putting the covering of the tank together, it simply cuts it oiwhereas if metal nails were used or screws were used and a bullethappened to strike the nail or screw at an angle, it would be likely tocut a long gash through the wood, rubber and the metal tank, which wouldbe much harder toA seal than a puncture made by the bullet alone.

The object in having a wooden layer on both sides of the rubber is asfollowszvReferring to Fig. 3, it will be assumed that a bullet is iredat the tank on the line X-X, the bullet going in the direction of thearrow in this figure. As the bullet enters, it seals up the hole in therubber on the side toward which it is traveling in the manner hereto.

fore explained. After it has passed through this opposite wall, however,and the metal inner container, it strikes the opposite wall ofthe tankand in passing through it seals up this hole in the rubber in exactlythe same way as first described and as illustrated in Fig. 5, but thebutton a is formed on the side of theA rubber nearest te the inside ofthe tank, instead of on the side of therubber nearest to the youtsideofthe tank. Now it will be obvious that if there was no inner layer ofwood 11, there would be no button formed on the side of the wall wherethe bullet last passed through, as the tin container or tank would benext to the rubber on theinside with no pulverized wood to fall in thepath of the bullet and plug the holes. v

It will be notedfromFig. 3 that I provide in one side wall of thecontainer, a nipple 25, this'nipple ,being provided with a head 26. Thehead 26 of the nipple is let intov the wood of the layer 11 and thenipple projects out through the rubber layer 12 and out through thewooden layer 13. A tight connection is made between `the nipple and theseveral layers by packing and cement and by a nut 27, which isscreweddown against the outside of the casing.' This nipple 25 is4 for thepurpose of ascertaining whether the rubber layer which extends all overthe tank is air tight and this is ascertained by pumping air into thenipple 25, there being a suit-- able pressure gage, not shown, attachedto the nipple. 25 by means of a T itting. The

l rubber must be air tight so that if a leak in the itin containerlft'occurs,v the rubber will retain the fluid for a reasonable length oftime. Inasmuch as the several nipples 15, 16 and 17 pass throughV boththe,woodand rubber, there is no Way ,for the air to get 'out exceptthrough some defect in the rubil ber or tin container. By plugging 'upall holes in the Acontainer but the opening-17,

and applying a pressure gage to the metallic container 14, proof can beimmediately had whether the rubber er the tin container is lea-king.

Of course the layer of rubber would slowly deteriorate were it incontact with the gasolene, but even where the rubber layer is in contactwith the gasolene, experiments have proved that the vulcanized jointsand the rubber layer will remain tight for several weeks. It will,therefore, be obvious that a mere puncture of the metallic tank and ofthe wooden inner layer will not affect the tan-k in any way as thegasolene, while it will come in contact with the rubber to some slightextent, will have very little effect thereon. Furthermore, the onlyobject of the construction which has been described is to enable theaviator to get back to his lines, which he will have to do within a fewhours at the longest. The plug formed by the con'nninuted wood coactingwith the rubber will be ample to prevent any leakage of gasolene, evenwhen the gasolene is under pressure for a considerable length of time.

The purpose of the nipple 25 as before stated is to provide meanswhereby the tank may be tested. The layer of cotton duck 18 is not.cemented to the tank 14, but is cemented to the woodenlayer 11.Therefore, there will be a free space all around between the duck 18 andthe container 14. Now if air under pressure is introduced into thenipple 25, it will be free to pass anywhere between the metal containerand the cotton duck. If a leak should exist in the tin container 14. theair would pass through the opening and with the pipes 15 and 16 closedup tight, a pressure gage disposed on the nipple 17 would show that airhad passed into the metal container 14 from the air pump, which isforcing the air through the nipple 25. It air should be delivered by thepump attached to the nipple 25 and no pressure show edv at the gage ornipple 17, then it would be proven that the air must either leak throughthe wood and rubber at some point or through the holes made in the woodand rubber for the nipples 15, 16 and 17 to pass. Thus I have provided ameans where.

by the tank may be tested ati intervals to show whether defectiveconditions exist or not. Of course mere cracks in' the wooden layerswould not affect the operative condi-vv willalso -be obvious that thedetails of construction which lI havedescribed may be images varied inmany ways, without departing at all from the spirit of the invention andthat I do not wish to be limited to these details, I have merelydescribed these details so as to indicate how a tank of a certain typemay be constructed.

Having described my invention, what l claim is 1. A selfpuncture-sealing tank including a wall formed of a layer of materialwhich, when perforated by a projectile, will provide a plug, and a layerof elastically expansible and contractible material which will beexpanded by the passage of a projectile through it and will thencontract to leave a relatively small passage into which said plug iscarried by the passage of the projectile.

2. A self puncture-sealing tank including a wall formed of a layer offibrous, brittle material, which, when perforated by a projectile, willbecome pulverized by the impact of the projectile, and a layer` ofelasticically expansible and contractible material disposed against thefirst named layer, which will be expanded by the passage of a projectile through it and will then contract to leave a relatively smallpassage into which the pulverized material will be drawn by the ight ofthe projectile, to thereby form a plug closing the passage.

3. A self puncture-sealing` tank including a wall formed of aninner'layer of metal, layers of relatively brittle, fibrous materialdisposed exteriorly of the metallic walls and spaced from each other,which material, when perforated by a projectile, will, becomepulverized, and an intermediate layer ofv elastically expansible andcontractible material which will be expanded by the passage 'of theprojectile and will then contract to leave a relatively small passagewhere the material has been perforated. c

4. A self puncture-sealing tank wall comprising an `inner layer ofmetal, two layers of relatively brittle, fibrous material disposedexteriorly to the metallic layer and spaced from each other, whichmaterial when perforated by va projectile will become pulverized by theimpact of the projectile, and an intermediatelayer of sheet rubberdisposed between the two fibrous layers and in contact therewith, whichwill be expanded by the passage of a projectile through it and will thencontract to leave a relatively small passage into which the pulverizedmaterial will be drawn by the flight of the projectile to thereby form aplug closing the passage.

5. A self puncture-sealing tank including an inner metallic containerand a sheathing surrounding the container composed of inner andputerlayers spaced from each other and] formed of material, which will becomecomminuted under the impact of a projectile, and an intermediate layerdisposed between said inner and outer layers and composed of materialwhich will elastically yield to the passage of a projectile andelastically contract t reduce the cross sectional area of theperforation.

6. A self puncture-sealing tank comprising an inner metallic containerand a sheathing therefor composed of alternate layers of wood andrubber, the layers being cemented to each other, and a nipple passingthrough the sheathing and communicating with the space between the innerlayer of the sheathing) and the metallic container and adapted to econnected to a source of air under pressure whereby to test the tank.

7. A self puncture-sealing tank comprising an inner metalliccontainerand a sheathing therefor composed of alternate layers of woodand rubber, the layers being cemented to each other, an inner layer ofcanvas cemented to the sheathing2 and a nipple passing through thesheathmgand the canvas Vand having a head at its inner end bearingagainst the inner layer of canvas and communicating with the spacebetween said layer of canvas and the container, the nipple being adaptedto be connected to a source of air under pressure whereby to test thetank.

In testimony whereof I hereunto aHix my signature in the presence of twowitnesses.

GEORGE J. 'MURDOCIL Witnesses:

JEANNETTE P. MURDOCK, WM. J. MURDOCK.

